U.S. patent application number 15/456258 was filed with the patent office on 2017-06-29 for reduced-friction catheter introducer and method of manufacturing and using the same.
The applicant listed for this patent is C. R. Bard, Inc.. Invention is credited to Eric M. King, Ronald Wortley.
Application Number | 20170182294 15/456258 |
Document ID | / |
Family ID | 36641642 |
Filed Date | 2017-06-29 |
United States Patent
Application |
20170182294 |
Kind Code |
A1 |
King; Eric M. ; et
al. |
June 29, 2017 |
Reduced-Friction Catheter Introducer and Method of Manufacturing
and Using the Same
Abstract
A sheath introducer for a catheter includes a sheath having a
lumen, a hub positioned on a proximal end of the sheath, and a
housing positioned on the hub. The hub can include a splittable
penetration member having a port in fluid communication with the
sheath lumen. The housing can include a valve having a closed upper
surface and a channel surrounding the splittable penetration
member. Movement of the housing with respect to the hub can expose
the port of the splittable penetration member for insertion of the
catheter.
Inventors: |
King; Eric M.; (Salt Lake
City, UT) ; Wortley; Ronald; (Salt Lake City,
UT) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
C. R. Bard, Inc. |
Murray Hill |
NJ |
US |
|
|
Family ID: |
36641642 |
Appl. No.: |
15/456258 |
Filed: |
March 10, 2017 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
11288959 |
Nov 29, 2005 |
9597483 |
|
|
15456258 |
|
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|
60631397 |
Nov 29, 2004 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
A61M 39/24 20130101;
A61M 2025/0046 20130101; A61M 25/06 20130101; A61M 25/0668
20130101; A61M 2039/2426 20130101 |
International
Class: |
A61M 25/06 20060101
A61M025/06; A61M 39/24 20060101 A61M039/24 |
Claims
1. A sheath introducer for a catheter, comprising: a sheath having
a lumen; a hub positioned on a proximal end of the sheath, the hub
including a splittable penetration member comprising a port in
fluid communication with the sheath lumen; and a housing positioned
on the hub, the housing including a valve comprising a closed upper
surface and a channel surrounding the splittable penetration
member, wherein movement of the housing with respect to the hub
exposes the port of the splittable penetration member for insertion
of the catheter.
2. The sheath introducer according to claim 1, wherein the valve
comprises a substantially flexible material, and the splittable
penetration member comprises a substantially rigid material.
3. The sheath introducer according to claim 1, wherein the valve
further comprises a ring sealing member disposed on an inner
surface of the valve, the ring sealing member extending radially
into the channel and in contact with the splittable penetration
member.
4. The sheath introducer according to claim 1, wherein the valve
further comprises a coating on an inner surface of the valve.
5. The sheath introducer according to claim 1, wherein the
splittable penetration member further comprises one or more stress
risers.
6. The sheath introducer according to claim 5, wherein the
splittable penetration member further comprises one of more notches
in a wall thereof.
7. The sheath introducer according to claim 5, wherein the one or
more stress risers includes a first stress riser on a first side of
the splittable penetration member and a second stress riser on a
second side of the splittable penetration member opposite the first
side.
8. The sheath introducer according to claim 7, wherein a portion of
the splittable penetration member further comprises a first notch
in the first side of the splittable penetration member and a second
notch in the second side of the splittable penetration member,
wherein the first notch is aligned with the first stress riser and
the second notch is aligned with the second stress riser.
9. The sheath introducer according to claim 1, wherein the valve is
made from a translucent or transparent material to provide a
flash-back chamber.
10. The sheath introducer according to claim 1, further comprising
a spring positioned between the housing and the hub, the spring
biasing the valve in a closed position.
11. A method for inserting a catheter into a body, comprising:
providing a tear away sheath introducer, comprising: a sheath; a
hub coupled to a proximal end of the sheath, the hub including a
splittable penetration member; a housing coupled to the hub, the
housing including a valve comprising a closed upper surface and a
channel surrounding the splittable penetration member; inserting a
distal portion of the sheath into the body; moving the housing with
respect to the hub to penetrate the upper surface of the valve with
the splittable penetration member; and inserting the catheter into
a port of the splittable penetration member, through the tear away
sheath introducer, and into the body.
12. The method according to claim 11, wherein the tear away sheath
introducer further comprises a dilator extending through the sheath
such that a distal end of the dilator is distal of the distal end
of the sheath, further comprising removing the dilator prior to
moving the housing.
13. The method according to claim 11, further comprising splitting
the tear away sheath introducer in two or more parts from around
the catheter such that the catheter remains in an inserted position
in the body.
Description
REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation of U.S. patent
application Ser. No. 11/288,959, filed Nov. 29, 2005, now U.S. Pat.
No. 9,597,483, which claims priority to U.S. Provisional
Application No. 60/631,397, filed Nov. 29, 2004, each of which is
incorporated herein by reference in its entirety.
FIELD OF THE INVENTION
[0002] The invention relates to medical devices and methods for
manufacturing such medical devices. In particular, the invention
relates to introducers for catheters, methods for making such
introducers, and methods for using such introducers. More
particularly, the invention relates to self-sealing sheath
introducers (both tear-away and non-tear-away), methods for
manufacturing such introducers, and methods of using such
introducers in medical procedures.
BACKGROUND OF THE INVENTION
[0003] Tear-away sheath introducers ("sheath introducers" or
"introducers") and their use as medical devices are well known in
the art. See, for example U.S. Pat. Nos. 6,814,718; 6,808,520;
6,808,509; 6,796,991; 6,740,101; 6,712,791; 6,712,789; 6,695,810;
6,641,564; 6,632,234; 6,623,460; 6,599,302; 6,361,559; and
5,558,652; as well as U.S. Patent Publication Nos. 2004/0260243,
2004/0254534, 2004/0176781, 2004/006330, 2004/097863, and
2002/072789, the disclosures of which are incorporated herein by
reference. These introducers are used in medical procedures to
insert a catheter into the body, thereby providing vascular access
to the vessel of a patient. The catheters are inserted via the
introducers by first using a needle to create an access site. A
dilator is then used to dilate the access site to allow a
larger-diameter sheath introducer to be introduced into the vessel
through the access site. The catheter is then inserted through the
sheath introducer and into the vessel. After the catheter has been
inserted, the sheath introducer is removed, leaving the catheter in
the vessel.
[0004] As shown in FIG. 19, conventional tear-away (or split)
sheath introducers 100 usually contain four major components: (1) a
dilator 140; (2) a tear-away sheath hub 111; (3) a tear-away valve
113; and (4) a tear-away sheath 130. The dilator 140 facilitates
insertion of the sheath introducer 100 into the vascular system and
maintains the inside diameter of the sheath 130 during insertion.
The dilator 140 is normally locked into the hub 111 in order to
keep it seated within the sheath 130. The dilator 140 typically
contains a tapered tip to facilitate insertion into the vascular
system with the proximal end 144 of the dilator 140 containing a
standard medical luer hub 146. Both the distal end 142 and the
proximal end 144 of the dilator 140 are usually manufactured of a
rigid polymer.
[0005] The tear-away hub 111 provides a means to contain the valve
113 while connecting the valve 113 and the sheath 130. The hub 111
typically has a "T" shape with the opposing ends of the "T" being
grasped and pulled to split both the valve 113 and sheath 130.
Thus, the hub 111 provides a mechanism to split the sheath 130 into
two portions and allow the introducer to be split and removed from
around the catheter. The hub 111 is also often manufactured of a
rigid polymer.
[0006] The tear-away valve 113, however, is typically made of a
flexible material (such as silicone) that provides a self-sealing
slit. The valve 113 may be designed as one piece that tears in half
during the splitting procedure, or as two (or more) pieces that
separate from each other during the splitting procedure. With
conventional introducers, the valve 113 is encapsulated by the hub
111.
[0007] The tear-away sheath 130 is normally manufactured as a
thin-walled structure, often as an extrusion. The extrusion
contains splitting means, i.e., score lines that facilitate
splitting or a self-splitting propagating material (such as
linearly-directional extrusion). The proximal end 132 of the sheath
130 is attached to the hub 111 using over-molding or any other
known attachment mechanism. The distal end 134 of the sheath 130
can be tapered to provide a smooth transition at the dilator/sheath
interface.
[0008] To use the introducer 100, it is inserted in the desired
vessel. Then the dilator 140 is unlocked from the hub 111 and
removed to allow room for a catheter (or any similar medical
device) to be inserted into the sheath. The valve 113 remains
stationary inside the hub 111 and blocks air and/or fluid from
flowing through the sheath 130 and hub 111 when they are left
behind after the dilator is removed. The valve 113 keeps the
passage 105 clear until a catheter is inserted into the passage 105
through the valve.
[0009] The introducer 100 is typically used for larger catheters,
i.e., those with a diameter of 12 to 16 French. These
larger-diameter introducers are rigid due to their diameter and the
material used to construct them. This rigidity allows the large
catheters to overcome the frictional forces needed to push the
catheter through the valve.
[0010] But inserting smaller catheters into smaller introducers is
more difficult. Typical introducers designed for smaller catheters
(i.e., those 3 to 12 French in diameter) are made with open
communication between the access site and the vascular system once
the dilator is removed. This open configuration exists because
smaller catheters, due to their smaller diameter and material, are
not rigid enough to overcome the frictional forces needed to push
the catheter through the valve. In other words, it is like trying
to "push" a rope through a hole: the rope does not remain rigid
enough for a user to push it through the hole.
[0011] The open configuration between the vascular system and the
environment, however, allows two serious clinical problems. First,
air embolism into the vascular system which can result in patient
injury and/or death. And second, release of potentially infectious
bodily fluids (including blood) into the environment, resulting in
exposure to the health care provider.
SUMMARY OF THE INVENTION
[0012] The invention relates to tear-away and non-tear-away sheath
introducers for catheters, methods for making such introducers, and
methods for using such introducers. The sheath introducers contain
movable valves that are encapsulated in a movable housing unlike
conventional valves that are stationary. The movable housing allows
the valve to move along the axis of the introducer. As the movable
valve and housing travel along the axis, a portion of the hub
protrudes past the valve and is exposed. The protruding portion of
the hub contains a friction-free pathway for the catheter into the
sheath introducer. The introducers can therefore be used with any
catheter, regardless of the size or material, because of the
reduced or eliminated frictional force between the catheter and
introducer.
BRIEF DESCRIPTION OF DRAWINGS
[0013] The following description of the invention can be understood
in light of FIGS. 1-19, in which:
[0014] FIG. 1 is a side perspective view(s) of the introducer
assembly in one aspect of the invention;
[0015] FIG. 2 is a side perspective view of a two-piece flexible
valve in one aspect of the invention;
[0016] FIG. 3 is a side perspective view of a dilator in one aspect
of the invention;
[0017] FIGS. 4 and 5 are section views of a valve housing in one
aspect of the invention;
[0018] FIGS. 6 and 7 depict the introducer assembly in another
aspect of the invention;
[0019] FIG. 8 is a side view(s) of the sheath introducer in another
aspect of the invention;
[0020] FIG. 9 is a side perspective view(s) of the sheath
introducer in even another aspect of the invention;
[0021] FIG. 10 is a side perspective view(s) of the sheath
introducer in yet another aspect of the invention;
[0022] FIGS. 11-12 show a single-piece valve in another aspect of
the invention;
[0023] FIGS. 13-14 depict view(s) of the single-piece valve and
sheath hub in another aspect of the invention;
[0024] FIGS. 15-17 depict view(s) of methods of increasing the
attachment between the sheath and the sheath hub in another aspect
of the invention;
[0025] FIG. 18 shows the operation or the sheath introducer in one
aspect of the invention; and
[0026] FIG. 19 illustrates a conventional sheath introducer.
[0027] FIGS. 1-19 presented in conjunction with this description
are views of only particular--rather than complete--portions of the
devices and methods of making the devices according to the
invention. Together with the following description, the Figures
demonstrate and explain the principles of the invention. In the
Figures, the thickness of layers and regions are exaggerated for
clarity. The same reference numerals in different drawings
represent the same element, and thus their descriptions will be
omitted.
DETAILED DESCRIPTION OF THE INVENTION
[0028] The following description provides specific details in order
to provide a thorough understanding of the invention. The skilled
artisan, however, would understand that the invention could be
practiced without employing these specific details. Indeed, the
invention can be practiced by modifying the illustrated method and
resulting device and can be used in conjunction with apparatus and
techniques conventionally used in the industry. For example, the
invention is described as a micro-introducer for small catheters (3
F-10 F in size), but could easily be adapted for any size of
catheter or device regardless of the size or intended use. Further,
while the invention is described for use with catheters for
vascular access, it could be used with any similar device that is
used to grant a physician (or other user) access to a part of the
body, whether human or animal.
[0029] The invention includes a tear-away or non-tear-away sheath
introducer that contains a movable valve and housing that when
moved, allows a portion of the hub to protrude through a valve and
be exposed. The protruding portion of the hub contains a
friction-free pathway for the catheter. Any inducer having these
properties can be used in the invention, including the sheath
introducer described below and illustrated in the Figures.
[0030] The sheath introducer of the invention contains several
primary components. First, dilator means used to dilate the
vascular system and create a pathway for the catheter. Second,
means for sheathing the dilator means to protect it from the
vascular system. And third, valve means for keeping the pathway
created by the dilator closed until the catheter needs to be
inserted.
[0031] One example of the sheath introducer is illustrated in FIG.
1 where the introducer 10 contains dilation means comprised of a
dilator hub 1 and a dilator shaft 2. The dilation means is
configured to fit within the sheath means comprised of a sheath hub
7 and a sheath 8. The introducer 10 also contains valve means
comprised of a valve with left and right halves (4 and 5) contained
within a valve housing having left and right halves (3 and 6) that
is attached to the sheath hub 7.
[0032] FIGS. 2-5 illustrate detailed views of each of these
components. FIG. 2 depicts one half of the valve 4, FIG. 3
illustrates the dilator hub 1, and FIGS. 4-5 show the different
views of one half of the valve housing 3. In FIG. 2, the valve
contains retention means for retaining the valve to the valve
housing. Any retention means known in the art can be used,
including retention member 12 which seats into a corresponding
structure in the valve housing such as the valve retention slot 15.
The valve has a size and shape substantially the same as the inner
part of the valve housing to which it is retained. Accordingly, the
valve half 4 depicted in FIG. 2 is substantially circular and with
a size that fits within the corresponding inner surface of the
valve housing 3 shown in FIGS. 4-5. The valve can be manufactured
from any suitable medical material, including flexible materials
like silicone or polyurethane.
[0033] FIG. 3 depicts one example of a dilator of the introducer
10. The dilator 31 can contain any standard medical luer hub,
including a dilator hub 1 with a gripping mechanism (such as finger
grips 11) and locking mechanism (such as locking ears 9) as shown
in FIG. 3. The locking mechanism 9 locks the dilator 31 into the
valve housing by using, for example, the locking channel 16
contained in the valve housing 3 and 6. The dilator 31 also
contains a shaft 2 with a tapered section for dilating the vessel
into which it is inserted. The dilator 31 can also be manufactured
from any suitable medical material, but should be made fairly
rigid, yet flexible enough that it can be maneuvered into the
desired vessel by a user.
[0034] FIGS. 4 and 5 depict one example of the internal geometry of
the valve housing 3. The valve housing 3 contains any means for
securing the valve housing to the sheath hub 7. In FIGS. 4 and 5,
the securing means comprises snap features 13, which secure the
valve housing 3 to the sheath hub 7 using the mating snap feature
21 (shown in FIG. 6). Using the securing means keeps the valve
housing (and therefore the valve) in a closed position until it is
needed to be opened (i.e., such as when the catheter is
inserted).
[0035] The valve housing 3 also contains any known means for
positioning it with the sheath hub 7. An example of this
positioning means is depicted in FIGS. 4 and 5, where a guide slot
15 and stop post 20 mate with the guidepost 22 of the sheath hub 7
(shown in FIG. 6). The exterior of the valve housing 3 contains
grips 14 that can be employed by the user in the splitting
procedure. The valve housing 3 is constructed of any suitable
medical material that provides the desired rigidity, such as rigid
polymeric materials.
[0036] The valve housing 3 can also contain any known interlock
mechanism between the two halves of the valve housing. An example
of this interlock mechanism is lock 19 that, when the halves are
assembled together, serves to maintain uniform travel between both
halves of the valve housing. This interlock mechanism can be
supplemented with any known mechanism, including the detachable
interlock features 17 and 18.
[0037] FIGS. 6 and 7 illustrate the various components of the
introducer when assembled together. In FIGS. 6 and 7, the sheath
hub 7 and the sheath 8 are attached together into an assembly by
any attachment means. Examples of suitable attachment means include
insert molding or any mechanical attachment, such as a friction
fit, locking snap fit, solvent or UV bond.
[0038] The sheath hub 7 also contains a valve penetration means.
The valve penetration means operates to penetrate the two halves of
the valve 4 and 5, thereby providing an opening in the valve. Any
penetration means known in the art can be used for this function.
As depicted in FIGS. 6 and 7, the penetration means comprise
penetration member 23 that is configured to fit between the two
halves 4 and 5 of the valve. The penetration member 23 opens the
two halves 4 and 5 of the valve when it is forced between them by
any action which pushes the penetration member 23 through the
valve.
[0039] The valve penetration means need not physically force (i.e.,
push) the valve halves 4 and 5 apart to penetrate the valve. In
this aspect, the penetration member 23 penetrates the valve halves
4 and 5 when the valve housings are pulled apart to expose the
penetration member 23. The valve housings 3 and 6 can be pulled
apart by the mechanisms described below.
[0040] When the penetration member 23 opens the valve in either of
these manners, port 24 is exposed. The port 24 is the location
where the catheter (or similar device) is inserted. Unlike the
conventional introducers where the catheter is forced between the
valve (which creates a friction force that must be overcome by a
user), the catheter can be inserted in the port 24 of the
introducers. The port 24 can be configured to have less friction
than that required in conventional devices by providing an inside
diameter slightly larger than that of the catheter insertion
member. Alternatively, the port can be configured to have
substantially no friction ("friction-free") by providing an inside
diameter significantly larger than that of the catheter insertion
member. As well, the port 24 can be configured to have less or
substantially no friction by providing a coating on the inside of
the port 24 and/or the outside of the catheter.
[0041] The sheath hub 7 also contains activation means. The
activation means is used to force the penetration member 23 up
through the valve halves 4 and 5, move the valve halves (and
housing) down over the penetration member 23, or to pull the valve
halves 4 and 5 apart, to thereby open them and expose penetration
member 23 containing port 24. Any mechanism that operates in this
manner can be use as the activation means. In the sheath hub
depicted in FIG. 7, the activation means pulls the valve halves 4
and 5 apart and comprises a reaction force member 25 that is formed
on the bottom edge of the sheath hub 7. When pressure is applied to
the reaction force member 25 by the user, it depresses the valve
housings 3 and 6 and forces the valve halves 4 and 5 apart. Of
course, any other known mechanism could be used to push or pull the
valve apart.
[0042] FIG. 8 depicts the introducer in a position ready to accept
a catheter. In FIG. 8, the penetration member 23 protrudes out of
the valve halves 4 and 5. The penetration member 23 need only
protrude enough so that port 24 is exposed enough for a catheter to
be inserted. Typically, the port 24 protrudes from about 0.025 to
about 0.05 inches above the valve. In one aspect of the invention,
the port 24 protrudes about 0.05 inches above the valve.
[0043] FIG. 9 depicts one part of a method for using the introducer
10. After the introducer 10 has been inserted into the desired
vessel, the catheter (not shown) is inserted through the introducer
10. Then, the user presses on the grips 14 to cause the valve
housing 3 and 6 to separate from each other. As the pressing
continues, the valve halves 4 and 5 and the sheath hub 7 then
separate from each other. Once this initial separation has
occurred, the user can continue pull on the ends of the separated
portions to continue separating the introducer 10.
[0044] FIG. 10 illustrates another part of a method for using the
introducer 10. In step 1, the introducer 10 has been inserted in
the desired part of the vascular system, i.e., the desired vessel.
Next, as shown in step 2, the dilator is then removed from the
introducer 10. As shown in step 3, removing the dilator still
leaves the valve in a closed position. Next, using the actuating
mechanism a user makes the penetration member 23 penetrate the
valve in any of the methods described above so that valve is opened
with the port 24 exposed. Then, the catheter (not shown) is
inserted into the introducer as shown in step 4. Finally, the
introducer is removed by the splitting procedure as shown in step
5.
[0045] The introducer described above can be modified and enhanced
with several optional features. One of these modifications is a
modified valve 30 as depicted in FIGS. 11 and 12 that comprises a
base 32, extensions 34, and channel portion 36. The base 32 of the
valve 30 is configured with a size and shape substantially similar
to the valve housing in which the valve 30 rests. The valve 30 can
optionally contain an indentation 35 of any shape and size that
will help the valve split.
[0046] The extensions 34 are designed to extend upwards from the
valve 30 towards the dilator of the introducer. Like the base 32,
the extensions 34 will abut the valve housing, but the sides rather
than the bottom. Accordingly, the size and shape of the extensions
34 are selected to substantially match the inner surface of the
valve housing which will enclose the valve 30. The extensions 34
contain a notch(es) 38 that correspond to the notches 50 provided
in the protruding member 41 (as described below).
[0047] The channel portion 36 of the valve 30 also extends in an
upward direction toward the dilator of the introducer. As shown in
FIG. 12, the inner surface 37 of the channel portion 36 will abut
the outer surface of the outside of the protruding member 41 and is
accordingly given a size and shape substantially matching the
protruding member 41. The length of the channel portion 36 is also
selected to substantially match the protruding member 41 so that
port 44 can be exposed when desired.
[0048] The upper surface 42 of the channel portion contains a slit
40. The slit 40 does not extend the entire way across the channel
portion 36 and so is a non-tear away slit. The slit 40 is held in a
closed or sealed position (position A in FIG. 13) by the valve
housing and sheath hub. The slit 40 moves into an open position B
when the protruding member 41 moves upward through the channel
portion 36 and then up through the slit 40 (or the valve 30 moves
downward over the member 41) as depicted in FIG. 13. Of course, as
described above, the valve 30 can be pulled apart to expose the
protruding member 41 rather than forced apart.
[0049] The channel portion 36 of the valve 30 can also operate as a
sealing means around the protruding member 41. The sealing means
helps provide a seal between the vascular system and the
environment when the protruding member 41 has forced the slit 40
open. This sealing function is illustrated in FIG. 13 where the
protruding member 41 is shown in its extended state, i.e.,
protruding above the valve 30. The channel portion 36 fits snugly
around protruding member 41 so that it provides a seal. Optionally,
a coating can be added to the inside of the channel portion 36
and/or the outside of the protruding member 41 to increase this
sealing function. As shown in FIG. 12, the channel portion 36 can
optionally contain a ring sealing member(s) 39 to increase the
sealing function.
[0050] The advantage of valve 30 is that it can also serve as a
flash-back chamber. If the valve 30 (and associated parts of the
hub sheath) is made from a translucent or transparent material, it
allows the user to view the inside of the valve 30. If sheath
introducer 10 is placed in the proper location (i.e., in the venous
system), blood will enter the valve chamber resulting in a red
color as an indication that the sheath introducer is placed
correctly. Using a translucent or transparent material for the
valve 30 therefore allows the user to look through the valve and
determine whether this red color is showing.
[0051] As mentioned above, a seal can be formed between the channel
portion 36 and the protruding member 41. To help improve the seal
between these two components, the protruding member 41 can be
modified by providing stress risers (45 and 46) on the inside 40
and the outside 41 of the protruding member 41 as shown in FIG. 14.
The internal stress riser 46 provides a smooth surface at the
interface with the valve ring sealing member 39. As noted above,
the valve ring sealing member 39 can provide a seal as the valve
translates along the stem. Moving from the bottom to the top of the
protruding member 41, the riser(s) 45 begin on the outside and then
move to the inside 46, allowing the splitting mechanism (crack) to
progress while maintaining a smooth outer surface between the valve
ring sealing member 39 and the protruding member 41.
[0052] The stress riser 45 begins on the bottom of the sheath hub
47 and continues along the outside of the sheath hub until the
stress riser 45 reaches a point below the initial location of the
valve ring sealing member 39. At that point, the stress riser 46
moves to the inside of the protruding member 41 and then continues
to the notch 50. The depth and width of the stress risers 45 and 46
are selected depending on the required separation force.
[0053] Another function of the stress risers 45 and 46 are to act
as an initiator in the splitting process. By their nature, the
stress risers are the beginning of a split in the hub sheath 47
and, therefore, can be used to make the splitting process easier.
Accordingly, the stress risers 45 and 46 are located substantially
on the axis where the introducer 10 will be split.
[0054] Another optional modification that can be made to the sheath
introducer comprises notches 50 in the upper portion of the
protruding member 41 that remain above the valve 30 in the extended
position. The notches 50 give the protruding member 41 additional
length to extend past the valve 30 while at the same time not
adding additional length to the stress risers 45 and 46. Such a
configuration adds length to the protruding member 41 without
increasing the cracking force needed to split the introducer
10.
[0055] As shown in FIG. 14, the notches 50 are generally made to
correspond with the same location as the stress risers 45 and 46,
i.e., substantially along the axis of the expected split. The
notches 50 can have any shape that results in a concentration of
the stress force. Examples of such shapes include substantial "V"
shape or the substantial rectangular shape shown in FIG. 14.
[0056] The sheath hub 47 can also be optionally modified to
increase the attachment between the sheath hub 47 and the sheath
53. One manner to increase this attachment is depicted in FIGS. 15
and 16. In FIG. 15, the sheath has been modified to contain a
sheath cap 57 with an interlocking fit between the sheath 53 and
the sheath cap 57. The sheath cap 57 contains grooves 58 which
provide a location for the split ends 55 of the sheath 53 when the
sheath is inserted though the sheath cap 57. The ends of the split
sheath fold around the sheath retention cap 57 with their location
maintained in the grooves 58. Once the sheath retention cap 57 is
assembled into the mating geometry of the sheath hub 47 as shown in
FIG. 16, it locks the ends 55 of the split sheath tightly into the
hub 47. The sheath cap 57 is then affixed to the sheath hub 47 by
means of a thermal, solvent or UV bond.
[0057] Alternatively, another method to increase this attachment is
depicted in FIG. 17. In FIG. 17, the sheath hub 47 has been
modified to encapsulate an end portion of the sheath 53. This
encapsulation is performed so that ridges 59 overly the end 56 of
the sheath 53, thereby retaining the end of the sheath underneath
the ridges.
[0058] In yet another modification, the sheath introducer can be
provided with means for separating the valve housing 33 away from
the sheath hub 47. Any known means for forcing these two components
apart can be used in the invention, including leaf spring, coil
spring, hinge, and/or a mechanical lever. As depicted in FIG. 18,
the forcing means comprises a spring 65. In its compressed state,
the valve housing 33 and the sheath hub 47 are attached to each
other by any mechanism, such as the snap features 13 and 21
mentioned above and/or the lever 66. When the valve housing 33 and
the sheath hub 47 are attached, the valve 30 remains closed. The
moment the user separates the sheath hub 47 from the valve housing
33 by pressing on the grip section 52 (and/or disengaging the lever
66), the spring 65 is released from its compressed state and these
two components separate from each other.
[0059] One result of the separation of these two components is the
movement of valve 30 relative to the protruding member 41. When
these two components are attached to each other, the spring is
compressed and the valve 30 slides down the protruding member which
then opens the slit 40 of the valve 30. When these components are
separated, the pressure of the spring 65 is released and it returns
to the uncompressed state, sliding the valve 30 back up the
protruding member and closing the slit 40.
[0060] In another modification, the valve housing of the introducer
could be engaged by means of a rotary movement along the axis of a
threaded member or any other mechanical means to translate the
valve housing along the desired path. For example, a mechanical
lever, push button, or threaded member could be used in this
modification.
[0061] In addition to any previously indicated variation, numerous
other modifications and alternative arrangements may be devised by
those skilled in the art without departing from the spirit and
scope of the invention and appended claims are intended to cover
such modifications and arrangements. Thus, while the invention has
been described above with particularity and detail in connection
with what is presently deemed to be the most practical and
preferred aspects of the invention, it will be apparent to those of
ordinary skill in the art that numerous modifications, including
but not limited to, form, function, manner of operations and use
may be made without departing form the principles and concepts set
forth herein.
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